https://doi.org/10.52973/rcfcv-e34392
Received: 17/02/2024 Accepted: 25/03/2024 Published: 28/06/2024
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Revista Científica, FCV-LUZ / Vol. XXXIV, rcfcv-e34392
ABSTRACT
Angiomyolipoma located on the caudal part of the abdominal wall
was reported in a 15–year–old femal bichon frise dog weighing 17 kg.
A radiographic examination was performed followed by a histological
examination of the mass, which revealed a benign encapsulated
mesenchymal proliferation composed of three compartments: vascular,
smooth muscle and adipose. The predominant adipose component is
made of large lobules of mature adipocytes. A blood chemistry prole
was performed revealing an increase in the activity of liver enzymes:
Gammaglutamyl transferase (12.90 IU·l
-1
), Aspartate aminotransferase
(70.1 IU·l
-1
), Alkaline phosphatase (403 IU·l
-1
); total, direct and indirect
hyperbilirubinemia were also noted (6.71 mg·l
-1
, 1.54 mg·l
-1
, 5.17 mg·l
-1
respectively). The management of angiomyolipoma requires surgery
which consists of the removal of the neoplasia mass to prevent local
progression. This clinical case is considered as the first case of
angiomyolipoma reported in canine veterinary medicine in Algeria.
Key words: Angiomyolipoma; radiographic examination; histological
examination; neoplasia; surgery
RESUMEN
Se noticó un caso de angiomiolipoma localizado en la parte caudal de
la pared abdominal en una perra Bichón Frisé de 15 años y 17 kg de peso.
Se realizó un examen radiográco seguido de un examen histológico de
la masa reveló una proliferación mesenquimatosa encapsulada benigna
compuesta por tres compartimentos: vascular, músculo liso y adiposo.
El componente adiposo predominante está formado por grandes lóbulos
de adipocitos maduros. Se realizó un perl químico sanguíneo que reveló
un aumento en la actividad de las enzimas hepáticas: gammaglutamil
transferasa (12,90 UI·l
-1
), aspartato aminotransferasa (70,1 UI·l
-1
), fosfatasa
alcalina (403 UI·l
-1
); También se observaron hiperbilirrubinemia total,
directa e indirecta (6,71 mg·l
-1
, 1,54 mg·l
-1
, 5,17 mg·l
-1
respectivamente).
El manejo del angiomiolipoma requiere cirugía que consiste en la
extirpación de la masa neoplásica para evitar la progresión local. Este
caso clínico se considera el primer caso de angiomiolipoma noticado
en medicina veterinaria canina en Argelia.
Palabras clave: Angiomiolipoma; examen radiográco; examen
histológico; neoplasia; cirugía
Subcutaneous angiomyolipoma in a bichon frise dog. Clinical case
Angiomiolipoma subcutáneo en una perra bichon frise. Caso clínico
Saber Beghoul
1
* , Amir Mansour
2
, Samir Djemai
1
1
Constantine 1 – Frères Mentouri University, Institute of Veterinary Sciences, Research Laboratory PADESCA. Constantine, Algeria.
2
Constantine 1 – Frères Mentouri University, Department of Medicine, Surgery and Reproduction, Institute of Veterinary Sciences, Algeria.
*Corresponding author: docteurbeghoul@gmail.com
FIGURE 1. Macroscopic view of the large mass on the caudal abdominal region
Subcutaneous angiomyolipoma in a bichon frise dog / Beghoul et al. _______________________________________________________________
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INTRODUCTION
Angiomyolipoma (AML; angiolipoleiomyoma) is an extremely rare
mesenchymal neoplasm in veterinary medicine [1]. These tumors
are composed of varying proportions of adipose tissue, smooth
muscle and thick–walled blood vessels [1, 2]. In humans, renal
angiomyolipomas, which usually develop without symptoms, are
found in approximately 80% of patients with tuberous sclerosis
complex (TSC). The fatty tissue in these neoplasms is generally
easily visualized by ultrasound and computed tomography, which
allows good monitoring of the tumor masses [3]. However, malignant
subtypes have been described in humans, particularly renal epithelioid
angiomyolipoma, which represents a very aggressive subtype with
metastatic potential and poor prognosis [1, 4]. The criteria of
histological aggressiveness of epithelioid angiomyolipoma are nuclear
anaplasia, mitotic activity, vascular invasion, presence of necrosis
and perinephric fat inltration [2, 5, 6]. The aim of this work is to
describe the stages of the clinical and paraclinical evaluation of a
case of a female bichon frise (Canis Lupus familiaris) who presented
with an angiomyolipoma in the subcutaneous tissue of the caudal
abdominal region, conrmed by histology. Surgical removal of the
tumor was successfully performed; the regular follow–ups carried
out after the surgery on the animal allowed us to conrm the absence
of recurrence or metastasis.
MATERIAL AND METHODS
Case history
A 15–year–old multiparous bichon frize dog weighing 17 kg and living
only indoors was presented to the ELOS veterinary clinic in Djebel
Ouahch, Constantine (Algeria) with a large mass in the caudal region
of the abdomen evolving for 6 weeks (FIG. 1). The animal appeared to
be in good overall health, with plenty of physical activity and a healthy
appetite. A general physical examination revealed no abnormalities:
normal rectal temperature (38.5°C; 101.3°F), normal cardiovascular
and respiratory parameters, non–reactive peripheral lymph nodes,
ocular and oral mucous membranes showed a normal color (pink) with
a good state of hydration, and capillary rell time was less than two
seconds. Palpation revealed a single large subcutaneous mass in the
caudo–ventral median abdominal region, painless, of rm consistency,
motionless and adhered to the abdominal wall.
In order to establish a denitive diagnosis, we carried out the
following paraclinical exams: a blood chemistry prole (BCP; including
blood glucose level, ionogram, bilirubinemia, liver enzyme activities)
was performed by Mindray BS– 200 clinical analyzer (CHINA), an
abdominopelvic X–ray (face: ventro–dorsal incidence and prole),
was performed by FDR Smart f Fujilm X–ray system USA and a
histopathological examination of biopsies collected from the mass
was performed using microscope Optika B–290TB Italy. Tissue
biopsies were xed in 10% neutral buffered formalin and embedded
in paran. Tissue sections were mounted on glass slides and stained
with hematoxylin and eosin (H–E) according to routine protocols.
RESULTS ANS DISCUSSIONS
The results of blood biochemistry analysis showed some
abnormalities (TABLE I): mild hyperalbuminemia (48.9 g·l
-1
), mild
hyperbilirubinemia (6.71 mg·l
-1
), with a slight increase in direct and
indirect bilirubin, slight increases in liver enzyme activities (Aspartate
aminotransferase (AST)=70.1 IU·l
-1
, Alkaline phosphatase (ALP) =
403IU·l
-1
, Gammaglutamyl transferase (GGT)= 12.9 IU·l
-1
).
The two radiographic images (ventro–dorsal and latero–lateral)
revealed an oval structure with soft tissue–like radiopacity, located in
the caudoventral region of the abdomen. X–ray examination conrmed
subcutaneous location of the mass and the presence of no other
abdominal and thoracic abnormalities (FIGS. 2, 3). In addition, the
ventro–dorsal radiographic image showed severe osteoarthritis on
both coxofemoral joints characterized by acetabular osteophytes
and femoral head deformity (Figure 2).
The histopathological appearance of the mass was compatible
with a tumor called angiomyolipoma, composed of three tissue
groups: vascular, smooth muscle and adipose (FIG. 4). The vascular
component included abnormal blood vessels with thick walls and
FIGURE 2. Frontal abdomino–pelvic X–ray images of the female dog showing the oval
structure with radiopacity similar to soft tissues (*) and coxofemoral osteoarthritis (**)
FIGURE 3. Lateral abdomino–pelvic X–ray images of the female dog showing the
oval structure with radiopacity similar to soft tissues (*)
FIGURE 4. Histological aspect of the cutaneous angiomyolipoma with these
three compartments: vascular (*), muscular (**) and adipose (arrow)
**
*
*
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Table I
Blood chemistry prole in bichon frise bitch
with subcutaneous angiomyolipoma
Test Results
Reference
range
Units
Sodium 148 143–154 mmol·l
-1
Potassium 3.83 3.9–5.6 mmol·l
-1
Chloride 114.4 106–116 mmol·l
-1
Glucose 0.64 0.67–1.35 mg·l
-1
Urea 0.15 0.08–0.3 g·l
-1
Creatinine 5.62 5–20 mg·l
-1
Total protein 72.24 55–78 g·l
-1
Albumin ↑ 48.9 28–42 g·l
-1
Creatine kinase (CK) 362 48–400 IU·l
-1
Bilirubin, total ↑ 6.71 1–6 mg·l
-1
Bilirubin, direct ↑ 1.54 <1.4 mg·l
-1
Bilirubin, indirect ↑ 5.17 < 3 mg·l
-1
Aspartate aminotransferase (AST) ↑ 70.1 16–54 IU·l
-1
Alanine aminotransferase (ALT) 82.1 18–86 IU·l
-1
Alkaline phosphatase (ALP) ↑ 403 20–320 IU·l
-1
Gammaglutamyl transferase (GGT) ↑ 12.9 2–10 IU·l
-1
lumens of varying sizes and shapes (FIG. 4B). The wall of dysmorphic
blood vessels is also characterized by the absence of the internal
elastic lamina. Smooth muscle cells appeared to arise from the
walls of blood vessels with a radial pattern (around the vessels). The
lipomatous component comprised mature adipose tissue containing
vacuolated mature adipocytes (stored lipids) (FIG. 4A).
We opted for the surgical treatment which consists in carrying out
the ablation of the examined mass and this, after having conrmed,
by histology, the benign nature of the tumor (angiomyolipoma).
Surgical removal of tumor was performed under general anesthesia.
After cephalic vein catheterization, premedication was performed
with acepromazine (0.05 mg·kg
-1
IV, CALMIVET
®
, VETOQUINOL, France),
followed by ZOLETIL
®
100 (IV, 7.5 mg·kg
-1
of tiletamine and 7.5 mg·kg
-1
of zolazepam, VIRBAC France) to provide general anesthesia.
The animal was placed in dorsal recumbency on a surgical table.
The skin at the incision site was carefully shaved, cleansed and
disinfected, after which a sterile surgical eld was placed. Surgical
removal of the tumor was performed by incising the skin surrounding
the mass and dissecting the subcutaneous tissue, after which we
resected the tumor parenchyma using a pair of sterile curved Mayo
FIGURE 5. Macroscopic appearance of the excised tumor mass having a large
size (length × width × height= 16×15×12cm) and weighing 1,410 g (3.1 lb) (A). The
section of the tumor, revealed a signicant ow of blood and clotted blood (B)
Subcutaneous angiomyolipoma in a bichon frise dog / Beghoul et al. _______________________________________________________________
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scissors, allowing complete excision of the tumor. Electrocoagulation
of the resected tissues was performed at the same time as the
resection, in order to stop the capillary hemorrhage.
The large blood vessels were isolated, clamped using haemostatic
forceps and then ligated with transxed surgical knots using absorbable
suture threads (USP size 3–0, polyglactin 910, Vicryl
®
Ethicon). After
removal of the tumor (FIG. 5), closure surgical wound was performed
according to standard surgical techniques, by performing a simple
continuous suture and a simple interrupted suture in order to
reconstitute the subcutaneous tissues and the skin, respectively.
Postoperative pain management was provided by two subcutaneous
injections of meloxicam at a dose of 0.2 mg·kg
-1
per day (METACAM
®
,
5 mg·ml
-1
, Boehringer Ingelheim Animal Health). The surgical wound
was regularly cleaned and disinfected until the lesion was fully
healed; systemic antibiotic therapy is provided by the administration
of Cefazolin Sodium at a dose of 25 mg·kg
-1
q12h IM (CEFAZOL
®
1 g)
during 10 days. Regular medical check–ups (including imaging) were
performed throughout a year to detect any return of the tumor.
Angiomyolipomas were relatively rare in dogs and their diagnosis
usually involved a combination of imaging techniques such as
ultrasound, CT scan (CT: computed tomography) or MRI (Magnetic
Resonance Imaging), as well as a biopsy. Extra–hepatic problems
could cause elevation of AST or ALP; increase in AST could indicate,
for example, muscle damage. Mild increase in ALP was dicult to
interpret in the dogs. In the absence of endocrinopathies or his
drugs use history inducing the production of ALP (corticosteroids
for example), hepatic hypoxia, mild cholestasis secondary to
hepatocellular damage seemed to be the most probable causes of
this elevation. However, the combination of elevation (in the female
dog examined) in AST (1.3–fold increase), ALP (1.2–fold increase),
GGT (1.3–fold increase) and bilirubinemia (1.18–fold increase) could
indicate cholestasis, although our animal did not show clinical signs
indicating liver damage [7].
Hemolysis and liver disease were the main differential diagnosis
of hyperbilirubinemia. The increase in unconjugated bilirubin (1.72
× increase in our case) in the blood indicated, in the rst instance,
hemolytic anemia which could be the result of an autoimmune disease
(immune mediated destruction) or a neoplasm [8]. The suspicion
in our case of moderate hemolysis explaining the unconjugated
hyperbilirubinemia cannot be excluded because the hematocrit was
not evaluated [7].
The histological appearance of the large mass observed in the
dog conrmed a cutaneous angiomyolipoma composed of three
compartments: smooth muscle tissue, mature adipose tissue
and abnormal blood vessels. Although smooth muscle cells were
predominantly spindle cells, they occasionally resembled rounded
epithelioid cells; occasionally, high levels of nuclear atypia
(multinucleation and mitotic activity) can be seen in these cells,
suggesting a possibility of malignancy [3].
The proportions of each of the three compartments (adipose,
muscular, and vascular) determined the typical radiographic
image of angiomyolipomas; mature adipose tissue was generally
the predominant component, allowing CT (computed tomography)
differentiation between renal angiomyolipoma and renal cell
carcinoma, two tumors affecting the human kidneys [9].
Angiomyolipoma was rarely found in veterinary medicine and only
four cases belonging to different animal species have been reported
and published: a uterine angiomyolipoma in a female dog [10], a renal
angiomyolipoma in a cat [11], a cutaneous angiomyolipoma described
in a female budgerigar (Melopsittacus undulates) [12] and a fourth
case of soft tissue angiomyolipoma in a Labrador female dog [2].
A retrospective study conducted in Switzerland between 2008 and
2013 using data from the Swiss Canine Cancer Registry revealed that
the most common canine cutaneous tumors (out of 11,740 cases of
canine skin tumors) were mast cell tumors (16.35%), lipomas (12.47%),
hair follicle tumors (12.34%), histiocytomas (12.10%), soft tissue
sarcomas (10.86%), and melanocytic tumors (8.63%) [13, 14].
Soft tissue sarcomas (18.40%), mast cell tumor (16.24%), lipoma
(9.69%), hair follicle tumors (9.34%), and benign sebaceous tumors
(8.50%) were the most frequently detected tumors out of 1,435
conrmed cases of cutaneous tumors in dogs in a retrospective
study conducted in Japan from 2008 to 2017 [15].
In Egypt, the five most prevalent types of cutaneous tumors
identied in a study conducted by [16] on 118 skin samples from
112 dogs were: basal cell carcinoma (8.47%), papilloma (7.63%),
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infundibular keratinizing acanthoma (6.78%), liposarcoma (6.78%),
and brosarcoma (5.93%).
Angiomyolipomas were mostly benign tumors; renal angiomyolipoma
tumors were the most prevalent benign kidney tumors in humans [17].
CONCLUSIONS
Angiomyolipomas were rare in veterinary medicine and can be
identied by three distinct tissues: muscle, vascular, and fatty. The
physical examination of the female dog, the blood biochemistry
prole and the radiographic and anatomopathological examinations
allowed us: to diagnose a cutaneous angiomyolipoma, to establish
the benign prognosis of the tumor and to opt for the surgical solution
allowing ablation of the large examined mass. Regular medical follow–
ups including imaging carried out over several months (up to twelve
months) revealed no recurrences.
Conict of interest statement
The authors declare that they have no conict of interest
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